Subject: Re: [ovs-dev] [RFC net-next 4/7] selftests: openvswitch: Add support for tunnel() key.

From: Aaron Conole <[email-masked]>
Date: Mon, 17 Jun 2024 13:56:46 -0400

Simon Horman <[email-masked]> writes:

> On Thu, Jun 13, 2024 at 02:13:30PM -0400, Aaron Conole wrote:
>> This will be used when setting details about the tunnel to use as
>> transport.  There is a difference between the ODP format between tunnel():
>> the 'key' flag is not actually a flag field, so we don't support it in the
>> same way that the vswitchd userspace supports displaying it.
>> 
>> Signed-off-by: Aaron Conole <[email-masked]>
>
> ...
>
>> @@ -1265,6 +1265,165 @@ class ovskey(nla):
>>                  init=init,
>>              )
>>  
>> +    class ovs_key_tunnel(nla):
>> +        nla_flags = NLA_F_NESTED
>> +
>> +        nla_map = (
>> +            ("OVS_TUNNEL_KEY_ATTR_ID", "be64"),
>> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_SRC", "ipaddr"),
>> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_DST", "ipaddr"),
>> +            ("OVS_TUNNEL_KEY_ATTR_TOS", "uint8"),
>> +            ("OVS_TUNNEL_KEY_ATTR_TTL", "uint8"),
>> +            ("OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT", "flag"),
>> +            ("OVS_TUNNEL_KEY_ATTR_CSUM", "flag"),
>> +            ("OVS_TUNNEL_KEY_ATTR_OAM", "flag"),
>> +            ("OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS", "array(uint32)"),
>> +            ("OVS_TUNNEL_KEY_ATTR_TP_SRC", "be16"),
>> +            ("OVS_TUNNEL_KEY_ATTR_TP_DST", "be16"),
>> +            ("OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS", "none"),
>> +            ("OVS_TUNNEL_KEY_ATTR_IPV6_SRC", "ipaddr"),
>> +            ("OVS_TUNNEL_KEY_ATTR_IPV6_DST", "ipaddr"),
>> +            ("OVS_TUNNEL_KEY_ATTR_PAD", "none"),
>> +            ("OVS_TUNNEL_KEY_ATTR_ERSPAN_OPTS", "none"),
>> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE", "flag"),
>> +        )
>> +
>> +        def parse(self, flowstr, mask=None):
>> +            if not flowstr.startswith("tunnel("):
>> +                return None, None
>> +
>> +            k = ovskey.ovs_key_tunnel()
>> +            if mask is not None:
>> +                mask = ovskey.ovs_key_tunnel()
>> +
>> +            flowstr = flowstr[len("tunnel("):]
>> +
>> +            v6_address = None
>> +
>> +            fields = [
>> +                ("tun_id=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_ID",
>> +                 0xffffffffffffffff, None, None),
>> +
>> +                ("src=", r"([0-9a-fA-F\.]+)", str,
>> +                 "OVS_TUNNEL_KEY_ATTR_IPV4_SRC", "255.255.255.255", "0.0.0.0",
>> +                 False),
>> +                ("dst=", r"([0-9a-fA-F\.]+)", str,
>> +                 "OVS_TUNNEL_KEY_ATTR_IPV4_DST", "255.255.255.255", "0.0.0.0",
>> +                 False),
>> +
>> +                ("ipv6_src=", r"([0-9a-fA-F:]+)", str,
>> +                 "OVS_TUNNEL_KEY_ATTR_IPV6_SRC",
>> +                 "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "::", True),
>> +                ("ipv6_dst=", r"([0-9a-fA-F:]+)", str,
>> +                 "OVS_TUNNEL_KEY_ATTR_IPV6_DST",
>> +                 "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "::", True),
>> +
>> +                ("tos=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TOS", 255, 0,
>> +                 None),
>> +                ("ttl=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TTL", 255, 0,
>> +                 None),
>> +
>> +                ("tp_src=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TP_SRC",
>> +                 65535, 0, None),
>> +                ("tp_dst=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TP_DST",
>> +                 65535, 0, None),
>> +            ]
>> +
>> +            forced_include = ["OVS_TUNNEL_KEY_ATTR_TTL"]
>> +
>> +            for prefix, regex, typ, attr_name, mask_val, default_val, v46_flag in fields:
>> +                flowstr, value = parse_extract_field(flowstr, prefix, regex, typ, False)
>> +                if not attr_name:
>> +                    raise Exception("Bad list value in tunnel fields")
>> +
>> +                if value is None and attr_name in forced_include:
>> +                    value = default_val
>> +                    mask_val = default_val
>> +
>> +                if value is not None:
>> +                    if v6_address is None and v46_flag is not None:
>> +                        v6_address = v46_flag
>
> By my reading, at this point v6_address will only be None if v46_flag is
> not None.  IF so, the condition below seems excessive.

Agreed - thanks for the suggestions.

>> +                    if v6_address is not None and v46_flag is not None \
>> +                       and v46_flag != v6_address:
>> +                        raise ValueError("Cannot mix v6 and v4 addresses")
>
> I wonder if we can instead express this as (completely untested!):
>
>                     if v46_flag is not None:
>                         if v6_address is None:
>                             v6_address = v46_flag
>                         if v46_flag != v6_address:
>                             raise ValueError("Cannot mix v6 and v4 addresses")
>
>> +                    k["attrs"].append([attr_name, value])
>> +                    if mask is not None:
>> +                        mask["attrs"].append([attr_name, mask_val])
>> +                else:
>> +                    if v6_address is not None and v46_flag is not None \
>> +                       and v46_flag != v6_address:
>> +                        continue
>> +                    if v6_address is None and v46_flag is not None:
>> +                        continue
>
> And I wonder if this is a bit easier on the eyes (also completely untested):
>
>                     if v46_flag is not None:
>                         if v6_address is None or v46_flag != v6_address:
>                             continue

I folded both of these in and did some quick testing.  Thanks Simon!

>> +                    if mask is not None:
>> +                        mask["attrs"].append([attr_name, default_val])
>> +
>> +            if k["attrs"][0][0] != "OVS_TUNNEL_KEY_ATTR_ID":
>> +                raise ValueError("Needs a tunid set")
>
> ...
>
>> @@ -1745,7 +1905,7 @@ class OvsVport(GenericNetlinkSocket):
>>          )
>>  
>>          TUNNEL_DEFAULTS = [("geneve", 6081),
>> -                           ("vxlan", 4798)]
>> +                           ("vxlan", 4789)]
>>  
>>          for tnl in TUNNEL_DEFAULTS:
>>              if ptype == tnl[0]:
>
> As noted in my response to PATCH 1/7, I think that the
> change in the hunk above belongs there rather than here.